Mount for electron discharge devices



March 28, 1939. c. P. VOGEL 2,151,816

I MOUNT FOR ELECTRON DISCHARGE DEVICES Filed Oct. 27, 19s? 7 INVENTOR CHARZEJ R VOGEL Patented Mar. 28, 1939 PATENT OFFICE MOUNT Eon ELECTRON DISCHARGE i DEVICES Charles P. Vogel, Millburn, N. 'J., assignor, by mesne assignments, to Radio Corporation of America, New York, N. Y., a corporation of Delaware Application October 27, 1937, Serial No. 171,243

4 Claims.

My invention relates to improvements in electron discharge devices, and more particularly to a mount construction in which the electrode assembly is firmly held in position in the envelope of the tube.

In radio tubes the electrode assembly should be supported firmly to'prevent transverse movement of the assembly with respect to the envelope. To this end the dome or constricted portion of the bulb used in tubes made with the dome type bulb is often utilized to steady the upper end of the electrode assembly and to prevent the electrode assembly vibrating transversely of the bulb or envelope of the tube. The electrode assembly should be steadied sufficiently to avoid noises, such as clicking, which may develop in operation and which are due to contact between the electrode assembly and envelope when the tube is jarred or vibrated while in use.

Inreceiving tubes where the matter of heating and high voltages is not particularly important resilient mica spacers of various kinds secured to the mount and extending between the mount and the envelope have been used to steady the mount within the envelope of the tube.

In connection with power output tubes however, it has been common practice to support mounts from the stem by a collar construction requiring elaborate bracing, heavy side rods and a supporting collar around the stem. The spacer between the elements of the mount is of necessity one having a high insulating characteristic and of substantial construction to resist high temperatures. The spacer is, therefore, usually of some ceramic material such as lavite. This material, however, cannot be used as a mount. support because of its rigidity and the fact that it cannot accommodate itself to the variations of bulb diameters. The use of mica as a spacer cannot be used in such tubes inasmuch as noise results when used in amplifier tubes due to leakage through the micas and because it deteriorates at the high temperatures encountered during exhaust of high power output tubes.

The object of my invention is to support the mount of a power output tube within the envelope of a tube by means of such character that it will not break down under high voltages or deteriorate at the high temperatures encountered during exhaust and at the same time provide the resiliency required for this type of, support.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figure l is a perspective showing the mount providedwith a support made according to my invention, Figure 2 is a top view of Figurel, and Figure 3 is, a side view partially in section of the construction shown in Figure 1, Figures 4 and 5 are top and side views of a modification of my invention, and Figure 6 is a detail in perspective of the elements comprising my invention and used in the construction shown'in Figures 4 and '5.

The electron discharge device shown in Figure 1 has a dome type envelope or bulb in, and may be provided with the conventional base and press, not shown. The mount II comprising the electrode assembly and the supports by which the electrode assembly is carried on the stem extends into the tubular portion or dome of envelope It]; On the upper end of the mount is an insulator I2 which may be in the form of a cross as shown and which is preferably of some ceramic material such as lavite for spacing the electrodes. This insulator is strong and rigid and is capable of withstanding high voltages applied between the various electrodes of the mount and the very high temperatures of the electrodes during exhaust. In the outer ends or edges of the spacer I2 are provided slots 13 as best shown in Figures 2 and 3 for receiving the inner edges of the mica spacer [4 provided with resilient fingers l5 contacting the inner wall of the tube envelope Ill. As best shown in Figure 2 this ring-like mica spacer I4 is provided with a plurality of cut-out portions or sections [6, these cut-out portions being of such dimensions that the ring-like spacer can be inserted over and clear the ends of the ceramic spacer l4 when the cut-out portions and the ends of the spacer are in registry with each other. The curves of the inner edges of the spacer M are formed so that the radii of the inner edges are of decreasing length moving in a clockwise direction with respect to Figure 2. When the mica spacer is inserted over the ceramic spacer and the inner edges of the mica spacer register with the transverse slots in the end of the ceramic spacer, the mica spacer may be locked in position relative to the ceramic spacer 12 by rotating the mica spacer in a counterclockwise direction. The resilient mica fingers engage the inner wall of the tubuluar portion of the tube envelope to resiliently support the mount within the tube envelope. In the position shown the mica spacer is outside of the portion of the tube subjected to high temperatures during exhaust and is also removed from those portions of the electrode mount subjected to high voltage differentials.

In the modification shown in Figures 4, and 6, the cross-like ceramic spacer 22 which spaces the electrodes of the mount assembly is provided with vertical slots 23 near the ends or edges of the ceramic spacer for receiving the U-shaped resilient micav spacers 24, the inner edges of which are engaged in the slots in the transverse lavite spacer 22. The outer edges of spacers 24 engage the inner wall of the dome of the envelope to resiliently support the mount.

While I have indicated the preferred embodiments of my invention of which I am now aware and have also indicated only one specific application ior which my invention may be employed, it will be apparent that my invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which it is employed Without departing from the scope of my invention as set forth in the appended claims.

What I claim as new is:

1. An electron discharge device comprising an envelope having a tubular portion, a mount comprising an electrode assembly positioned in said envelope and extending within the tubular portion, a ceramic spacer secured to said mount to extend transversely of the tubular portion of the envelope for spacing and supporting the electrodes of the mount, and spacers of resilient sheet insulation mounted on said ceramic spacer and secured to the outer portions of said ceramic spacer and extending between said spacer and the envelope andin contact with the walls of the envelope to resiliently support the end of the mount in a predetermined position within the envelope.

2. An electron discharge device provided with an envelope having a tubular portion, a mount comprising an electrode assembly supported in said envelope and extending within said tubular portion, a cross-shaped ceramic insulator securedto said mount to extend transversely of the tubular portion of the envelope to space and support the electrodes of the mount assembly, and provided with slots near the ends of the arms of the ceramic insulator and extending longitudinally of the tubular portion of the envelope, and U- shaped insulating members of sheet insulating material mounted perpendicularly to said ceramic spacer and having their inner edges engaged in the slots in said spacer and contacting the walls of the envelope of the tube for resiliently supporting the end of the mount in a predetermined position, within said envelope.

3. An electrondischarge device comprising an envelope having-a tubular portion, a mount comprising an electrode assembly positioned in said envelope and extending within the tubular portion, a ceramic spacer secured to said mount to extend transversely of the tubular portion of the envelope for spacing and supporting the electrodes of the mount and spacers of resilient sheet insulation mounted on said ceramic spacer and positioned between said spacer and the envelope, and in contact with the walls of the envelope to resiliently support the end of the mount in a predetermined position within the envelope.

4. An electron discharge device comprising an envelope having a tubular portion, a mount comprising an electrode assembly positioned in said envelope and extending within the tubular portion, a ceramic spacer secured to said mount to extend transversely of the tubular portion of the envelope for spacing and supporting the electrodes of the mount, and spacers of resilient sheet insulation positioned on the outer portions of the ceramic spacer and extending between the spacer and the envelope and in contact with the walls of the envelope to resiliently support the end of the mount in a predetermined position within the envelope.

CHARLES P. VOGEL. 

